This invention relates to a new applicator, and more specifically to a new prefilled applicator for administration of semi-solid medications such as creams and the like to the vagina and other body cavities.
The use of vaginal applicators for application of medication is well known in the art. There are currently a number of applicators on the market for application of semi-solid medications to the vagina. In general, compliance of vaginal treatments with medications of this type is largely dependent on the applicator used. It is therefore necessary to employ applicators that are as comfortable and easy to operate for the user as possible and that do not produce irritation or pain. They must also fulfill a number of additional requirements, such as simplicity and economy of manufacture. It is also very important that they can be used both as a container for the medication and as a device for dispensing the medication, thus avoiding any handling by the user. This handling, apart from being cumbersome and messy, makes it impossible to guarantee the hygienic conditions necessary for this type of device and that the correct dosage of the medication is applied. In order to be used as a container, the device must seal off the compartment where the medication is stored. In this case, it is also important for the applicator to be easy to fill with the medication at the factory.
Most applicators on the market do not fulfill many of these requirements. They usually comprise a straight, hollow cylindrical body with a small diameter and a plunger stem movable within the cylinder, and they are usually intented for repeated use. One of the ends of said cylinder is open and generally contains an inner thread, allowing it to be threaded to a tube containing the vaginal medication. In order to use the applicator, the medication tube must be screwed into the open end of the applicator. The opposite end of the tube is then squeezed, forcing the medication into the applicator. Then, the tube is unscrewed and the applicator is ready for use. This type of applicator cannot be used as a container, i.e, they cannot be prefilled with the medication, because they do not provide an air-tight seal, which means that the user must fill the applicator before each use, with the resulting possibility of error in dosage, hygiene loss and the inconvenience of the loading process for the user.
Some applicators suitable for being prefilled with medication have been described in the literature.
U.S. Pat. No. 2,630,804 discloses a prefilled vaginal applicator wherein for compactness purposes the body of the applicator is provided as a telescoping assembly comprising inner and outer tubes. A piston is disposed closing one end of said inner tube and the other end is closed by means of a plug. A telescoping piston rod is disposed inside the inner tube, through a hole in the piston. In use, telescoping rod assembly must be first extended, then telescoping barrel assembly must be extended to its full length by sliding outer barrel along inner barrel, and finally extended piston rod must be pulled and brought into locking engagement with the piston. While providing a compact device, this applicator is difficult to use, since three operations are needed to assemble the applicator before use, and there is also a risk of disassembling the telescoping barrels during use if the user pulls too strong during the second operation. Moreover, this applicator may cause discomfort during use since it is not rounded at its dispensing end.
U.S. Pat. No. 4,636,202 describes a vaginal applicator provided with an automatically-opening closure for the dispensing end of the applicator body.
WO 93/21986 describes a vaginal applicator comprising a barrel having a large diameter cylindrical section, a small diameter section and a sloped transition section together with a twist off cap and a rubber plunger provided with a piston rod. The twist off cap is used both to close the dispensing end and as a rod to push the piston rod and expel the medication. In use, the cap must be removed by twisting it off, then must be inverted and reinserted within the large diameter section, and pushed to expel the medication. This applicator is difficult to use since it involves disassembly and reassembly of the cap.
For these reasons, a new, improved vaginal applicator is necessary that can solve these and other problems that will become clear throughout the description.
It is the object of the present invention to provide a vaginal applicator that can be used both as a container and a device for dispensing the medication, which contains a minimum number of parts, which is inexpensive to manufacture and easy to assemble and fill with the medication in the factory as well as easy and convenient to operate for the user.
This object is achieved by the features of claim 1.